What Kind of Trim/Tilt Fluid

I have a 1999 Johnson 150 hp. I was wondering what kind of of fluid goes into the trim/tilt reservoir. I was wondering will ATF be ok?

Re: What Kind of Trim/Tilt Fluid

ATF Dexron III is fine. I dont like mixing oils though personally, so I would drain the old stuff first.

Re: What Kind of Trim/Tilt Fluid

Thanks a lot.

Re: What Kind of Trim/Tilt Fluid

HighTrim, How do you drain the old stuff ??

Re: What Kind of Trim/Tilt Fluid

boobie said:

HighTrim, How do you drain the old stuff ??

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I used the device that is used to put gear lube in the lower unit to suck out all the old fluid from the system. I then used ATF Dexron 3. Are you saying I should not have used the ATF? After filling the reservoir up I can not get the hydraulics to lift the motor at all. I am trying to lift the motor with the manual release valve in the open position because my screw head looks like it getting wider and wider. I don't want to keep turning it until I finish bleeding the system. I need to get a new manual release valve screw before I'm unable to use it anymore. Does that screw just screw all the way out if I want to replace it?

Re: What Kind of Trim/Tilt Fluid

I have used different suction or pressure techniques. I used to be anal about getting it all out, but have to admit now I just drain the bulk of it and be done with it.

You will need to bleed the system as you know, and add more fluid as you do. Cycle 5 to 6 times, leave in the up position, fill, cycle 5 to 6 times, leave in the up position, fill, etc.... until you can fill no more.

Re: What Kind of Trim/Tilt Fluid

dwelch022 said:

I then used ATF Dexron 3. Are you saying I should not have used the ATF?

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some types of oils do not mix. They congeal and form globs of goo. Brake fluid and motor oil is an example.

I've never had problems mixing old oil with new as long as the old fluid is clean and clear. Water in oil is always bad and should be resolved immediately before bypass valves, gears, or sensors get rusty. Dirty oil with black stain is a sign of oring damages. Industrial hydraulics eventually wear out the oil. The pump gears shear it and eventually break it down. I doubt any recreational boat has ever come close to that much trim/tilt use.

the problem with a complete fluid drain while still on boat is air under pistons. you fill reservoir with engine raised. if system is fully drained then there is nothing under pistons except air. Air bubbles under piston can be a real PITA on some trim systems. In the shop, it's no problem. You simply fill the open rams with oil before assembly. maybe .... if ... you fill system while raised .... lower the engine using manual release ... tighten manual release and raise .... maybe that would get the air bubbles out enough and you wouldn't have to go through a long multi-cycle bleeding ... maybe.

Re: What Kind of Trim/Tilt Fluid

Thanks RRitt I'll give it a try!